Diffs

Visual diffs compare consecutive snapshots pixel-by-pixel to detect changes. When a monitor captures a new screenshot, the system automatically generates a diff against the previous snapshot. Each diff includes the percentage of pixels that changed, a heat-map image highlighting the changed regions, and a significance flag based on your threshold setting. Requires Starter plan or above.

List diffs

Returns visual diffs for a monitor, with the most recent first. You can filter by date range and change percentage — for example, to find only significant changes above a certain threshold. Each diff links to its before and after snapshots, so you can download both screenshots for comparison.

GET/v1/monitors/{monitorId}/diffs

Query parameters

Parameter	Type	Description
`created_after`	string	Filter diffs created after this date
`created_before`	string	Filter diffs created before this date
`min_change_percent`	number	Only diffs with at least this change %
`max_change_percent`	number	Only diffs with at most this change %
`is_significant`	boolean	Filter by significance flag
`sort`	string	`created_at` (default), `change_percent`
`order`	string	`desc` (default) or `asc`
`per_page`	integer	Items per page (default: 20)

bash

# Get significant changes only
curl "https://api.snapshotarchive.com/v1/monitors/42/diffs?is_significant=true" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Accept: application/json"

$client = new \GuzzleHttp\Client();
$response = $client->get('https://api.snapshotarchive.com/v1/monitors/42/diffs', [
    'headers' => [
        'Authorization' => 'Bearer YOUR_API_KEY',
        'Accept' => 'application/json',
    ],
    'query' => [
        'is_significant' => 'true',
    ],
]);
$data = json_decode($response->getBody(), true);

import requests

response = requests.get(
    "https://api.snapshotarchive.com/v1/monitors/42/diffs",
    headers={
        "Authorization": "Bearer YOUR_API_KEY",
        "Accept": "application/json",
    },
    params={"is_significant": "true"},
)
data = response.json()

const response = await fetch("https://api.snapshotarchive.com/v1/monitors/42/diffs?is_significant=true", {
    headers: {
        "Authorization": "Bearer YOUR_API_KEY",
        "Accept": "application/json",
    },
});
const data = await response.json();

require "net/http"
require "json"

uri = URI("https://api.snapshotarchive.com/v1/monitors/42/diffs?is_significant=true")
http = Net::HTTP.new(uri.host, uri.port)
http.use_ssl = true

request = Net::HTTP::Get.new(uri)
request["Authorization"] = "Bearer YOUR_API_KEY"
request["Accept"] = "application/json"

response = http.request(request)
data = JSON.parse(response.body)

req, _ := http.NewRequest("GET", "https://api.snapshotarchive.com/v1/monitors/42/diffs?is_significant=true", nil)
req.Header.Set("Authorization", "Bearer YOUR_API_KEY")
req.Header.Set("Accept", "application/json")

client := &http.Client{}
resp, _ := client.Do(req)
defer resp.Body.Close()

Response

200 OK

{
  "data": [
    {
      "id": 15,
      "monitor_id": 42,
      "change_percent": "12.50",
      "pixel_count_changed": 50000,
      "pixel_count_total": 2073600,
      "is_significant": true,
      "snapshot_before": { "id": "abc-123", "captured_at": "2026-09-29T12:00:00Z" },
      "snapshot_after": { "id": "def-456", "captured_at": "2026-09-30T12:00:00Z" },
      "created_at": "2026-09-30T12:00:05Z"
    }
  ],
  "meta": { "current_page": 1, "per_page": 20, "total": 8, "last_page": 1 }
}

Get a diff

Retrieves a single diff with its heat-map image URL. The diff_image_url is a signed URL pointing to a PNG that highlights changed areas in red. The response also includes the full monitor object and both snapshot references.

GET/v1/diffs/{id}

bash

curl "https://api.snapshotarchive.com/v1/diffs/15" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Accept: application/json"

$client = new \GuzzleHttp\Client();
$response = $client->get('https://api.snapshotarchive.com/v1/diffs/15', [
    'headers' => [
        'Authorization' => 'Bearer YOUR_API_KEY',
        'Accept' => 'application/json',
    ],
]);
$data = json_decode($response->getBody(), true);

import requests

response = requests.get(
    "https://api.snapshotarchive.com/v1/diffs/15",
    headers={
        "Authorization": "Bearer YOUR_API_KEY",
        "Accept": "application/json",
    },
)
data = response.json()

const response = await fetch("https://api.snapshotarchive.com/v1/diffs/15", {
    headers: {
        "Authorization": "Bearer YOUR_API_KEY",
        "Accept": "application/json",
    },
});
const data = await response.json();

require "net/http"
require "json"

uri = URI("https://api.snapshotarchive.com/v1/diffs/15")
http = Net::HTTP.new(uri.host, uri.port)
http.use_ssl = true

request = Net::HTTP::Get.new(uri)
request["Authorization"] = "Bearer YOUR_API_KEY"
request["Accept"] = "application/json"

response = http.request(request)
data = JSON.parse(response.body)

req, _ := http.NewRequest("GET", "https://api.snapshotarchive.com/v1/diffs/15", nil)
req.Header.Set("Authorization", "Bearer YOUR_API_KEY")
req.Header.Set("Accept", "application/json")

client := &http.Client{}
resp, _ := client.Do(req)
defer resp.Body.Close()

Diff threshold. Set diff_threshold_percent on the monitor to control sensitivity. A value of 5 means only changes affecting 5% or more of the page are marked as significant. Lower values detect more changes but may trigger on ad rotations or timestamps.